My goal is to radically shift our approach to prevention. I want to leverage online advertising, social media and smartphone technology to create a rapid, effective and scalable platform for targeted prevention messages that actually shift health behaviors. I plan to start with skin cancer prevention, using tanning beds and melanoma as the proof-of-principle example. However, this work will be broadly generalizable to many other public health challenges where behaviors play a key role in the disease process. Over half of cancers are preventable through behavioral changes, vaccines, or medications.1,2 However the process of moving from scientific evidence to implementation is painfully slow. Recent Institute of Medicine and RAND reports estimate that only 50% of recommended health care practices are implemented, and this takes decades. The situation is even worse for preventive health care. Meanwhile, both melanoma and non-melanoma skin cancer (NMSC) rates continue to increase.3 4 In fact, incidence of skin cancer is higher than all other cancers combined. Indoor tanning is a class I carcinogen and a major, modifiable risk factor that accounts for over 450,000 new NMSC and over 10,000 melanomas each year.5 This is close to half a million potentially preventable skin cancers each year. Yet, tanning bed use remains common with 1 in 5 adolescents and over 40% of college students using tanning beds in the last year.5 Despite significant investment in prevention efforts, including well-designed campaigns by foundations focused on skin cancer prevention, our efforts to impact incidence of skin cancer have hit a brick wall. Technology to target health messages can get the right message to the right person at the right time. Social media and online search engines give us an unprecedented ability to target our health messages directly to those at highest risk. These platforms give us a way to direct a message precisely when teens are ? for example ? searching for a tanning salon.7,8 Over 90% of teens and young adults are online daily, and 92% engage with two or more devices simultaneously-including smartphones, tablets, PC and TV.9, 10 The most efficient way to reach the largest number of young adults is through the technology they are using, including: social media, online search engines and smartphones. Online advertising works to shift attitudes towards consumer brands, and shift purchasing behaviors. Therefore, this approach could be used to shift indoor tanning attitudes and behaviors. The advantages of leveraging advertising on social networking and search sites include: 1) unprecedented reach, 2) relatively low cost, and 3) the opportunity to target specific audiences. First, we will use a mixed-methods approach to learn which messages are most engaging. Then we will test which messages are most effective at shifting knowledge and self-reported tanning behaviors using two online randomized trial designs. Finally, we will run a large national trial to test whether these messages shift actual tanning bed use and melanoma incidence.